1. Technical Field
Exemplary embodiments of the present invention relate to a semiconductor memory device, and more particularly, to a 3-dimensional (3D) stack memory device.
2. Related Art
With the rapid development of mobile and digital information communication and consumer-electronic industry, further improvements upon existing electronic charge devices are expected to encounter the limitation. Thus, new functional memory device other than the existing electronic charge device needs to be developed. In particular, next-generation memory devices with large capacity, ultra-high speed, and ultra-low power consumption need to be developed.
Currently, resistive memory devices using a resistive device as a memory medium have been suggested as the next generation memory devices and there are typically phase change random access memory (PCRAM), resistive RAM (ReRAM), and magentoresistive RAM (MRAM).
The resistive memory device may be basically configured of a switching device and a resistive device and stores data “0” or “1” according to a resistance state.
Even in the resistive memory devices, the first priority is to improve an integration density and to integrate memory cells in a narrow area as many as possible. Furthermore, when the plurality of memory cells are integrated in a limited area, switching performance has to be ensured.